Respiratory apparatus



J. M. GANZER. RESPIRATORY APPARATUS.

APPLICATION FILED FEB. 20. l9l8.

Patented July 22, 191-9.

- INVENTOR 3 SHEETS SHEET I.

ATTORNEY J. M. GANZER.

RESPIRATORY APPARATUS.

APPLICATION FILED FEB. 20. 1918.

Pateljted July 22, 1919.

3 SHEETS-SHEET 2.

J. M. GANZER. RESPIRATORY APPARATUS.

APPLICATION FILED FEB. 20. I9I8.

Patented July 22, 1919.

3 SHEETS-SHEET 3- ATTORNEY JOHN M. GANZER, 0F POUGHKEEPSIZ E, NEW YORK.

RESPIRATORY APPARATUS.

Specification of Letters Patent.

Patented July 22, 1919.

Application filed February 20, 1918. Serial No. 218,270.

To all whom it may concern:

Be it known that 1, 'JOHN M. GANzER, a citizen ofthe United States, andaresident of the city of Poughkeepsie, county of Dutchess, and State ofNew York, have invented certain new and useful Improvements inRespiratory Apparatus, of which the following is a specification,reference being had to the accompanying drawings.

Although I shall herein describe and illustrate the invention -asembodied in a gas mask, it will be obvious to those familiar with suchmatters that many, indeed, practically all of its features may beemployed wherever a supply of air suitable for human respiration isdesired to be assured, as, for instance, by firemen, miners, in chemicalworks, in refineries, at high altitudes, and elsewhere, and that certainof its features are applicable in submarine work.

In such structures as heretofore made cer-' tain desiderata, some ofwhich are quite es sential for the reliable operation of the apparatus,have been insufiiciently provided for and some not at all. It is thepurpose of this invention, therefore, to so construct and correlate thevarious parts of the apparatus that they shall individually andcollectively greatly increase the healthful and life-saving operationthereof.

Generally stated, the invention includes means whereby the'mask may beheld firmly upon the face of the wearer in such manner that all jointsbetween the'edges of the apparatus and the face of the wearer shall beeificiently sealed, thus preventing the entrance or seepage ofdeleterious gases, smoke, fumes, or air, from the exterior to theinterior. It also includes improved means whereby the joints between alledges of the apparatus and the face of the wearer may be securelysealed; also means whereby the air once used and partially devitalizedmay be ejected from the apparatus, either into the atmosphere, or into asuitable receptacle for vitalization; also means whereby the fogging ofthe eye pieces may be avoided; also means whereby the device will, uponapplicationto faces of diferent shape and size, automatically adjustitself thereto; also means whereby double protection is afforded thewearer, that is to say, injury tothe hood or eye piece section will notinterfere with the respirator-y portion of the apparatus; also meanswhereby respiration may be either through the nose or mouth, or both;

also an improved construction and arran e ment of the harness, or headstraps, where y the apparatus is held upon the face of the wearerfirmly, yet without painful pressures, and the permanence of all sealedjoints effectively maintained.

In the drawings Figure 1 is a side elevation of an apparatus embodyingmy invention shown as in use upon the face of the wearer, the profile ofthe wearer being shown in dotted lines; Fig. 2 is a vertical sectionalview of the invention shown in Fig. 1; Fig. 3 is an elevation, partlybroken away, showin the construction of certain of the parts 0 therespiratory portionof the apparatus viewed from the rear; Fig. 4. is anelevation of the parts shown in Fig. 3 viewed from the front; Fig. 5 isa horizontal plan view, partly in section, taken on the line 55 of Fig.3.

Referring to the drawings, I will first describe the parts composing therespiratory portion of the apparatus, 2'. 6., those which cover andprotect the nose and mouth of the wearer and supply air from the sourceof supply to the lungs and convey away the used air therefrom.

1 represents the mouth piece, 2 the nose piece. As shown best in Fig. 2,the mouth piece is of a general cwpshape, e., it has a rounding orarched exterior surface 3, 3,

and a substantially circular rim 4, the upper) part of which rim engageswith the upper lip and checks of the wearer adjacent to the corners ofthe mouth and the lower part of which rim engages with the face of thewearer from about the corners of the mouth down to and under the chin.The nose piece 2. is generally hollow semi-pyramidal, in form and-has arim which is substantially triangular and is the part which contactswith the face of the wearer. Allthe forwardly arched projecting parts ofthe nose I piece are curved or arched. The ridge 5 isfree passage ofair'from the interior of the mouth piece to. the interior of the nosepiece. In the outward or forward partof the mouth piece there isprovided a cavity 9,

from which extends an air passage 10 upwardly to the outside of the n sepiece where it is provided with a flutter valve 11, the openings 11* ofwhich, in the example shown, occur at its corners and which, in a mannerwell understood, permit exit of air passing upwardly through the saidpassage, but prevent entrance of air downwardly therethrough.

Across the open side of the cavity 9 in the forward part of the mouthpiece there 10 is arranged a flexible diaphragm l2, whlch maybeneficially be made of thin and exceed- 1 ingly flexible rubber, whichwill retain lts flexibility and integrity for a long time. The edges 13of the diaphragm are so connected at or near the edges of the cavity 9,that while they are hermetically sealed thereto, the body portion of thediaphragm is bag or pouch like in form, and is not in contact with anypart of the apparatus, so that its inward and outward movements are notin any manner interfered with or hampered.

The lower part vof the mouth piece is extended downwardly, as shown at14-, and within it is located a short section of tubing, 15, the upperpart of which in the example shown, forms part or a couple of valvecasings, one arrangedhorizontally and the other vertically, and thelower art of the so tubing afiords means to which t e air supply pipe 16may be attached.

1? is a horizontally disposed valve set in a suitable casing in theupper part of the tubing 15 and which I prefer shall be of as the wellknown clapper variety made of flexible rubber fastened centrally andhaving a ribbed edge and which permits the passage of air from thesupply pipe 16 upwardly into the mouth piece, but precludes at itspassage in theopposite direction.

18 is an opening made in the side of the tubing 15, below the valve 17.It connects with a passage 19 located in the wall of the mouth piece andwhich opens into the cavity 9. 20 1s a'vertrcally disposed valve locatedin the opening 18, and so constructed that as the diaphragm 1-2 is drawninwardly by the inhalation of the wearer, thus tending to produce avacuum in the cavity 9, it will open and permit air from the source ofsupply through the supply pipe 16 to pass through it upwardly andthrough the passage 19 into the cavity 9 and upon the movev ment of thediaphragm 12 in the opposite direction due to the exhalation of thewearer, the valve 20 will instantly close and compel the air in thecavity 9 to move upwardly through the passageway 10 and the Y fluttervalve 11 and out through its openings 11 into the space inclosed by theb ood, as

hereinafter more fully explained.

21 is a flutter valve which connects with a passage 22, which opens intothe interior of the nose iece, and 23 is a similar flutter valve whitconnects with a'passage 24, made preferably along the ridge of the nosepiece, and opens into the space between the hood 25, the face of thewearer, and the exterior of'the respiratory members of the apparatus, 5.e., the nose and mouth pieces.

At all of the edges of the mouth and nose pieces, which constactwith theface of the wearer, I provide a peculiarly constructed seal, which isbest illustrated in Fig. 3, that is to say; the edges of these parts,all of which are made of vulcanized rubber, are rolled over uponthemselves, as shown at 26, and preferably terminate in a somewhatenlarged and solid core, edging piece, or beading, 27 which extendslongitudinally throughout all the edges of the entire seal, or fringe,as I call it, upon both the nose and mouth pieces, and it will be noted,as shown at 28, that this same form of seal extends across the upperpart of the mouth piece so as to effect engagement with the upper lipand checks of the wearer to approximately the corners of the mouth,where it vanishes, or thins away, into the part 29 of the main fringe,which extends around and under the chin of the wearer.

The hood 25 is provided with eye pieces 30, which may be of anypreferredconstruction and material. making the body of the hood asheretofore, I prefer, although this is not essential, that it also shallbe made of pure rubber similar to that from which the diaphragm 12 ismade, except that it may beneficially be heavier and stronger, becauseif so, its durability, elasticity and ability to Withstand rough usageare greatly increased. As shown in the drawings, it is connected at itslower part to the downwardly extending projection 14.- from the mouthpiece and extends upwardly and rearwardly therefrom in substantially theform shown. It is also preferably, although not necessarily connected tothe exterior front surfaceof the mouth piece, and provision is made forthe passage through'it of the flutter valves 21 and 23. The hoodincloses, as usual, the entire respiratory portion of the apparatus andmakes air tight contact throughout all its edges with the face,forehead, chin and cheeks of the wearer.

The straps, or harness, which .coniine the apparatus, to the head of thewearer, are as follows: 31 is a head strap. Instead, however, ofstarting at the upper edge of the hood, as usual, it isextendeddownwardly between the eye pieces and preferably quite to the end of thenose piece of the interior respiratory portion of the apparatus,although of course on the exterior of the hood, and 1s cemented, orotherwise fastened to the hood along the ridge of the nose'piece andalso preferably across the forehead and the hood itself is similarlypreferably far tened to the ridge of the nose piece. The

Instead, however, of v purpose of this construction is so that the headstrap, which is extremely important in use and is the part whichfrequently gives way under strain, may have firm and reliable engagementor connection with the respiratory appliances, so that the nose piece,and through it the mouth piece, may both be pulled upward and the nosepiece simultane- 1 ously backward against the face of the harness, orother appropriate part.

ing this strap to the edge of the hood, as

usual, I extend it as shown best in Fig. 1,

clear across the front of the mouth piece, where it is rigidly connectedby cement or riveting, or in any other suitable and reliable manner, tothe exterior arched or curved surface of the mouth piece. It' may beattached to the mouth piece either inside or outside of the materialforming the hood.

If inside, then suitable sealed openings should be made therein, thatitmay pass to the exterior thereof. This strap 32 is one contmuous ieceand passes across the front of the mout piece, so that reliance need notbe placed upon the strength or permanence of the stated cementingmaterial or riveting,

or any other fastening devices which may be used, the function of whichis merely to re-' tain the strap in proper position relative to themouth piece. This particularity is desirable because the snugness withwhich the mouth piece is pressed against the upper lip and about thecheeks and chin of the wearer and likewise the snugness with which thenose piece isheld' at its lower part, where it is connected with themouth piece, will largelydetermine the air tightness ofthe vitallyimportant parts of the apparatus.

The strap 32 passes around the head of the K wearer, as usual, and isconnected in the rear with the head strap 31, or the part to which it.is connected, as the case maybe, and is provided at its free end with adevice, such as a buckle 33, whereby it is detachably attached to therigidly fastened end 34. Between thehead strap 31 and the mouth strap 32there is a forehead strap 35, which is preferably continuous andencircles the head of the 'wearer,passing acrosshis forehead at theupper edge of the hood,

where it is connected thereto, and around to the rear of the head of thewearer where it is connected to the head and mouth straps, or the art towhich they are connected, as usual. he head, forehead and mouth strapsmay be made of strongly elastic material, or embody" elastic sections,so as to make the harness adjustable automatically to heads of varyingsize and contour; or, if preferred, they may be inelastic, orsubstantially so, their tension being'regulated by the degree oftightness with which they are applied. While, as stated, all of thestraps, slnce they are continuous and inclose the parts of the apparatuswhere they are located, do not rely upon the hood to resist the strainsto which they are subjectedfstill it is desirable that they be cemented,o-r otherwiseattached to the hood at or near its edges, so that they mayaid in properly distending the hood and adjusting it upon the head ofthe wearer. It will be particularly noted that the connections betweenall straps and the respiratory devices, 2'. 0., either the nose or themouth iece, are made at points far removed from t e edges of therespiratory devices where they contact with the face of the wearer.Consequently the said edges and the seal thereon are free to adjustthemselves to the special conformation of the particular face upon whichthey may be applied. 4

The operation of the-apparatus is asfollows, and it will be particularlynoted that a series of highly important results are secured,- which, sofar as I know, have never been attained heretofore and which materiallyenhance the efficiency of the apparatus as a healthpreserving and lifesaving mechanism.

The apparatus is applied to the face of the wearer by first snuglyadjusting the mouth and nose pieces over the mouth, nose and chin. In sodoing, the upper edge of V the nose piece makes contact with the bridgeof the nose, the upper edge of the mouth piece makes contact with theupper lip, and the lower edge of the mouth piece makes contact with thechin, and the side edges of the nose and mouth pieces make contact withthe cheeks and jaws. The harness is then passed over the head of thewearer, as usual, and adjusted to position, and the mouth strap is drawntaut and fastened by the buckle or other device, whereupon the severalstraps will securely hold the apparatus in position about the face'ofthe 'wearer, and since all the straps are continuous and do not relyupon the strengthjof the edges of the hood to resist their strain, beingonly connected therewith sufficiently to secure its proper distensionabout the face of the wearer, there is no danger of rupturing the hood,either at its edges or at any other part.

The nose and mouth pieces are obviously the controllingly essentialfeatures of such an apparatus and it will be noted that the mouth piece,being, as stated, in the general form of a hollow cup, its outer surfaceeX- from the face of the wearer in all directions, so that when themouth strap 32 is drawn with sufficient tightness, the mouth piece,

which may be said to be the foundation of the respiratory portion of theapparatus, will be drawn snugly against the upper lip, cheeks and chinof the wearer, and that owing to its arched formation in all directions,it is capable of resisting considerable pressureexerted by the strap 82,and yet the pressure transmitted through it to the upper lip, face andchin of the wearer will be distributed throughout the entire area of therim of the mouth piece and will not exert painful pressure even after anextended use. It will also be noted that the nose piece is similarlyarched in all directions and its free edges have an inclinationrearwardly,

so that when applied to the face .of the wearer, as in Fig. 2, its upperpart, which engages with the bridge of the nose, and the graduallyspreading edges, which engage with the cheeks of the wearer, will bepressed snugly against them, partly because of the resiliency of thematerial of which they are formed, but more particularly because of theupward and inward pulling action of the head strap'31, so that thecombined action of the head strap 31 .and the mouth strap 32 and thepeculiar formation of the nose and mouth sections, cause all the edgesof the respiratory portion of the apparatus to be held in permanent andclose contact with the face of the wearer, and in order that the jointthroughout may be permanently maintained and rendered securely airtight, the peculiar rolled construction of the fringe or seal isproduced upon all of the edges in question and thus secures much betterresults than have ever been attained heretofore, so far as l am aware,because the socalled pneumatic cushions become practically useless ifpunctured, and the rubber of which they are formed, evenif-softlyvulcanized, is far too rigid to automatically adjust itself air tight tothe difl'erent shapes,

sizes and irregularities of the faces and heads of difi'erent wearers.The action of the curled over seal or fringe is peculiar, that is tosay, as pressure is exerted upon it, the rolled over or curled contournormally present in it enabl its rolling or curling action to beextended or increased, and in so doing the elasticity due to theresilient character of the material of which it is composed, 27. e.',rubber, adds to the sealing effect due to pressure, and inasmuch as theseal, or fringe, upon the edges of both the mouth piece and nose pieceis laterally expandible and contractible, it will be readily seen thatconnected with a suitable source of air supply, as, for instance, acanister carried by the wearer, or some exterior and more remote sourceof air, as the case may be, inhalation, either through the nose ormouth,or both, has a tendency to create avacuum in the open spaces of the noseand mouth pieces, which can only be satisfied by the entrance of airthrough the tube 16 and valve 17, which in response to the suction thusformed, immediately opens and air passes upwardly into the mouth pieceand through it and from it through the openings 8 into the nose piece,and will be inhaled by the wearer through the nose or mouth, or

both, and then exhaled again through one or both,as the case, may be. Assoon as the valve 17 closes, which will be upon the cessation of inflowof air to the mouth and nostrils, the exhaled air will escape throughthe Each inhalation, which, as stated, tends to produce a vacuum in themouth and nose pieces, will also draw the flexible diaphragm 12 upwardlytoward the lipsv of the wearer,

thus of course tending to create a vacuum in the cavity 9 in front ofthe diaphragm,

and this will open the valve 20 and cause some of the air from thesupply pipe 16 to pass into the cavity 9, and upon the succeedingexhalation the diaphragm 12 will be flexed in the opposite direction,away from the lips of the wearer, which will contract the area of thecavity 9 and instantly close the valve 20, whereupon the air in thecavity will be forced upwardly throughthe passageway 10 "and the valve11 and escape'at the outside of the nose piece into the space betweenthe hood and the face of the wearer, and each successive inhalation andexhalation operating in the same manner will speedily generate a certainamount of air pressure in the space between the hcEd and the face of thewearer which will open the valve 23, permitting the escape of excess airwithin that space, and thus the hood will be ventilated and fogging ofthe eye pieces efiiciently prevented.

I call particular attention to the following, and as l believealtogether new features, that is to say: since the diaphragm 12 iscontinuously pumping airinto the space be-' tween the hood, the face ofthe wearer and the exterior surfaces of the respiratory portion of theapparatus, there 1s, as stated above, always more or less pressure withmhood and the face of the wearer, or any leaks in the hood itself, itwill always be from within outwardly and cannot be from withoutinwardly, and consequently by no possibility can any noxious vapors orexternal air get into the hood, much less within the respiratory portionof the apparatus which is additionally isolated and sealed against suchseepage. Also fogging of the eye pieces 1s occasioned mostly at least byreason of the exhaled, warm and moisture containing air, and it will benoted that in the devices shown, no part of the exhaled air can everreach the eye pieces.

It will be obvious to those who are familiar with such matters thatcertain features of my invention are useful without the presence ofcertain others, that is to say: the respiratory portion of theapparatus, 2'. e., the nose and mouth pieces, with'their associated andco-acting parts may be beneficially used by themselves without any.exterior hood, which is all that is necessary in most cases of firefighting and in many other cases where assurance of respiration of pureair is all that is requisite; also the respiratory devices and a hoodwithout the hood ventilating features may be useful in many cases, inwhich event, the diaphragm l2 and its associated and co-acting parts maybe omitted; also in cases where respiration through the mouth onlyis'necessary, the

mouth piece only need be employed, in which event, of course, theflutter valve 21 will be connected with the interior of the mouth piece,as at the opening 8.

As a matter of convenience, or economy in manufacture, itmay be moreexpedient to make the several parts, or some of them, as separate piecesand cement, or otherwise connect them in the form and adapted to fulfiltheir several functions, as above described. I advance no instructionsor directions in this regard because such form no part of my invention.

In conclusion, I believe that there never before has been produced anapparatus of this class which affords such assurance of protection tothe wearer and such comfort and reliability in use, because, for thereasons above stated, the possibility of any inward assage of deadly,noxious, or objectionab e vapors, gases, fumes or air, is quiteeffectively prevented, and yet the necessary amount of air forrespiration assured; no

objectionable pressures other than are insep-- arably incident to suchan apparatus are brought upon the face or head of the wearer; nomechanical means for closing the nostrils and no objectionable anddangerous mouth plugs are required, on the contrary, respiration iscarried onin the usual and normal manner.

miliar with such matters that the apparatus" above described andillustrated is one form only in which my invention may be embodied andthat modifications may be made therein without departing from theessentials of the invention.

I claim:

1. In an apparatus of the class stated, a hollow mouth piece, a hollownose piece, both made of flexible material, an air passage connectingthe two, an air. inlet for the mouth piece, a check valve in the inletto permit inward and prevent outward passage of air, an outlet for usedair from the mouth and nose pieces, a heck valve in the outlet to permitoutward and prevent inward passage of air, a hood surrounding the mouthand nose pieces and engaging with the face of the wearer, means to bothpermit the entrance of air to, and prevent its exit from, the hood,other means to both permit the exit of air from, and prevent itsentrance to, the hood, means actuated by the respiration of the wearerwhereby air is forced into and out of the hood, and means to firmly holdthe apparatus against the face of the wearer.

In an apparatus of the class stated, a hollow mouth piece, a hollownosepiece, both made of flexible material and arched throughout theirexterior surfaces, an air passage connecting the two, an air inlet forthe mouth piece, a check valve in the inlet to permit inward and preventoutward passage of air, an outlet for used air from the mouth and nosepieces, a check valve in the outlet to permit outward and prevent inwardpassage of air, a hood surrounding the mouth and nose pieces andengaging with the face of the wearer, means to both permit the entranceofairto, and prevent its exit from, the hood, other means to both permitthe exit of air from, andprevent its entrance to, the hood, meansactuated by the respiration of the wearer whereby air is forced into andout of the hood, and means to hold the apparatus firmly against the faceof the wearer;

3. In an apparatus of the class stated, a hollow mouth piece, a hollownose piece, both made of flexible material, a sealing device upon allthe edges of the mouth and nose pieces which contact with the face andchin of the wearer, an air passage connecting nose pieces and engagingwith the face of v the wearer, means to both permit the en- 7 trance ofair to, and prevent its exit from,

the hood, other means to both permit theexit mo of air from, and preventits entrance to, the hood, means actuated by the respiration of thewearer whereby air is forced into and out of the hood, and means tofirmly hold the apparatus against the face and; chin of the wearer.

4. In an apparatus of the class stated, a

hollow mouth piece, a hollow nose plece,

both made of flexible material, an air passage connecting the two, anair inlet for the mouth piece, a check valve in the inlet to permitinward and prevent outward passage of air, an outlet for used air fromthe mouth and nose pieces, a check valve in the outlet to permit outwardand prevent inward passage of air, a hood surrounding the mouth and nosepieces and engaging with the face and air thereto and therefrom, a hoodwhich in-' closes the mouth and. nose pieces, means to permit theentrance of air to, and exit from, the hood, and continuous straps whichhold the mouth and nose pieces firmlyagainst the face of the wearer.

6. In an apparatus of the class stated, a hollow mouth piece, a hollownosepiece, suitable'means for the entrance and exit of air thereto andtherefrom, a hood which incloses the mouth and nose pieces, means topermit the entrance of air to, and exit from, the hood," a continuousstrip which presses against the mouth piece remote from its edges and isattached to the hood adjacent to its edges, and other straps whichinclose the hood and are connected thereto adjacent to its edges.

7. In an apparatus of the class stated, the

respiratory portion whereof comprises a hollow-mouth piece and a hollownose piece provided with suitable means for the entrance and exit of airthereto and therefrom, sealing devices which surround and separatelyinclose the mouth piece and the nose piece, the edges of which makecontact with the forehead, cheeks, jaws and chin, a hood which inclosesthe nose and mouth pieces, a continuous strap which passes acrossthemouth piece and is attached to the exterior of the hood, anothercontinuous strap WlllCh passes across and embraces and is attached 'tothe upper part of the hood, and another continuous strap attached to thehood and extendmg vertically over the ridge of the nose piece, betweenthe eyes, across the forehead and over the head of the wearer, the saidstraps being so connected thereto and to the hood as to firmly hold theapparatus in desired position.

8. In an apparatus of the class stated, flexible devices adapted tocover the mouth and nose of the wearer and provided with suitable meansfor the entrance and exit of.

trance and exit of air thereto and there from, sealing devices attachedto all the edges of said mouth and nose pieces .respec' tively whichcontact with the face, upper lip and chin of the wearer, a hood whichincloses the said mouth and nose devices, and means to firmly hold theapparatus in desired position.

10. In an apparatus of the class stated, devices adapted to cover themouth and nose of the wearer and provided with suit ble means for theentrance and exit of air thereto and therefrom, a sealing device for theedges of said mouth and nose devices which contact with the face andchin of the wearer, ahood which incloses the said mouth and nosedevices, means actuated by the respiration of the wearer whereby air isforced into and out of the hood, and means to firmly hold the apparatusin desired position:

11. In an apparatus of the class stated, devices .adapted to cover themouth and nose of the wearer and provided with suitable means for theentrance and exit of air thereto and therefrom, a sealing. device uponall the edges of said mouth and nose devices mouth and nose devices theedges whereof make contact with the face and chin of the wearer, meansto create and maintain atmospheric pressure within the hood, and meansto firmly hold the apparatus in desired position. r

12. In an apparatus of the class stated, a sealing device for the ed esof the respira-' tory portion thereof whifir contact .withthe face andchin of the wearer, consisting of a piece of flexible, air-tightmaterial rolled over inwardly upon itself, a cross section of whichtaken at any part presents the contour of a volute.

13. In an apparatus of the class state embodying a respiratory portionand a hood, means to ventilate the hoodconsisting of a cavity in therespiratory portion the open side whereof is closed by a member. adaptedto be moved to and fro by the respiration of the wearer, means to bothpermit the entrance of air to, and prevent its exit from, the cavity,and other means to permit the passage of air from the cavity into thehood and prevent its return to the cavity, means for the escape ofexcess air from the hood, and means to firmly hold the apparatus indesired position.

14. In an apparatus of the class stated, embodying arespiratory portionand a hood, means to create a circulation of air through the hood,consisting of a pump actuated by the respiration of the wearer whichalternately draws air inwardly to the interior of the pump and ejects ittherefrom into the hood, and means to firmly hold the apparatus indesired position.

15.11 an apparatus of the class stated, embodying a respiratory portionand a hood,

means to supply air to the interior of the.

hood consisting of a cavity in the respiratory portion the open sidewhereof is closed by a flexible diaphragm confined at its edges only,its remaining portions being free from.

contact with anything and adapted to be moved to and fro by therespiration of the wearer, means upon inhalation to both permit theentrance of air to, and prevent its exit from, the cavity, othermeansupon exhalation to both permit the passage of air from the cavityinto the hood and prevent its return to the cavity, means to permit theescapeof excess air from the hood and means to firmly hold the apparatusin desired position. t

Intestimony whereof I havename'to this specification.

JOHN M. GANZER.'

signed my-

